Process of making thioindigo leuco compounds.



UNITED STATES PATENT OFFICE-.-

iiiiiLiN 'IION or GERMANY.

GERMANY, ASSIGNOR TO BADISCHE PROCESS OF MAKING THIOINDIGO LEUCO COMPOUNDS.

To all whom it may concern:

Be it known that I, EDUARD MUNoH, doctor of philosophy and chemist, a subject of the Grand Duke of Baden, residing at Lud- Wigshafen-on-the-Rhine, Germany, have in vented new and useful Improvements in Producing Leuco Com ounds of Thioindigo Coloring-Matters, of w ich the following is as ecihcation.

n the specification of the application for Letters Patent Serial No. 451250, filed Sep.

1 1908 I havedescribed the production of omega dihalogen vinyl thiosalicylic acid compounds by acting on certain tliiosalicylic acid compounds with trihalogenethylene.

have discovered that these omega-dihalogen-vinyl-thiosalicylic acid compounds on treatment with an alkaline condensing agent can be made to yield leuco compounds ofcoloring matters of the thioindigo group. I can carry out the condensation of the omegarlihalogen-vinyl-thiosalicylic acid compounds for instance with caustic soda, caustic potash, mixtures thereof, and alcoholates of these metals. If desired, other agents ma be used at the sametime, for instance meta lic carbonates, alkaline earth hydrates, diluting agents, and fluxes. The reaction may also be carried out under pressure. The condensation products thus obtained are leuco compounds of the so-called thioindi 0 colorin matters, for instance omegaichlorviny thiosalicylic acid, when treated with an alkaline condensing agent, chiefly yields 3-oxy-(1)-thionapthene-Z-carboxylic acid, or a mixture of this compound with 3-oxy-'(1)- thionapthene. I

The following examples will serve to illustrate further the nature of my invention and how it can be carried into practical ef- -fect, but it is not confined to these examples.

The parts are by weight.

Example 1. Mix to ether'four (4) parts of omega-dichlor-vinyl-t iosalicylic acid, four (4) parts of calcined soda and six (6) parts each of caustic soda and caustic otash, and hen heat the mixture in an oi -bath to a =nperature of from one hundred and twent mm (125), to one hundred and fifty (150) egrees centigrade, whereupon reaction takes place and gas is evolved. vHeat the result- Specification of Letters Patent.

Application filed September 1, 1908.

which Patented Jan. 26, 1909.

Serial No. 451,252.

ing yellow melt for thirty (30) minutes at from two hundred (200), to two hundred and ten (210), degrees centigrade. Dissolve the melt, when cold, in water, add hydrochloric acid and filter off and dry the product from 3-oxy-(1)-thionapthene carboxylic acid can be obtained in the pure form by extraction with benzene.

Example 2. Heat, in a metal bath at about two hundred (200) degrees centigrade, a mixture of four (4) parts of omega-dichlorvin l-thiosalicylic acid and four (4) parts sac of caustic soda and caustic potash, whereupon reaction takes place and a yellow melt is obtained. Continue heating for thirty (30) minutes, dissolve in Water, and acidulate with hydrochloric acid. Upon distillation with steam 3-oxy-(l)-thionaphthene passes over and-separates in the form of fine needles.

Example 3. Introduce five (5) parts of omega-dichlor-vinyl-thiosalicylic acid into a boiling solution of sodium alcoholate, repared from ten (10) parts of sodium; istil off the alcohol, gradually raising the temperature to from two hundred and ten (210), l .to two hundred and thirty (230), degrees centigrade, and heat till a yellow melt is obtained, from which the leuco com ound can be obtained in the manner descri ed in the foregoing Exam le 2.

Example 4. Peat in an oil-oath, at from one hundred and fifty (150), to one hundred and seventy-five (175), degrees centigrade, a mixture of equal parts of ome a-dichlorvinyl-para-brom-thiosalicylic aci calcined soda, caustic soda and caustic potash, whereupon reaction soon takes place and a brownyellow melt is obtained. Dissolve the cold melt in water, and recipitate, b ineans of hydrochloric acid, lilie resulting euco compound of para-para-dibrom-thioindigo.

- Now what I claim is:

1. The process of producin leuco compounds of coloring matters of are thioindigo group by acting with an alkalinecondensing agent on an omega-dihalogen-vinyl-thiosalicylic, acid compound.

2. The process of producin leuco compounds of coloring matters of. t e thioindigo group by acting with an alkaline condensing agent on omega dihalogen-vinyl-thiosalicylic In testimony whereof I have hereunto set acid. 1 my hand inthe presence of two subscribing 3. The process of produciin leuco con1- witnesses. pounds 0f coloring matters of t e thioindigo EDUARD MUN CH. 5 group by acting with caustic soda, caustic Witnesses:

potash and calcmed soda. on omega-dihalo J. ALEO. LLOYD, gen-vinyl-thjosalicylic acid. R. A. SIGBBEE. 

